Scotland scrum-half Ali Price is out of the World Cup because of a foot injury suffered in Sunday's defeat by Ireland.
The Glasgow Warriors player, 26, came on as a second-half substitute in place of Greig Laidlaw in the 27-3 loss in Yokohama.
Edinburgh's Henry Pyrgos will fly out as Price's replacement.
It comes a day after Scotland lost back-row Hamish Watson for the rest of the tournament, with Magnus Bradbury called up to replace him.
"We're disappointed for Ali to have to return home so early in the tournament," said Scotland head coach Gregor Townsend.
"Both Ali and Hamish invested a lot of effort in being in their best physical shape for the World Cup and it's a shame they've only been involved in one game.
"However, we have a lot of belief in our wilder group and the two new players who have been given this opportunity."
Scotland face Samoa in their next Group A match in Kobe on Monday (11:15 BST), before meetings with Russia and Japan.